1. Field of the Invention
This invention relates to a system, method and apparatus for monitoring operation of a conveyor belt.
2. Description of Related Art
It relates in particular, though not exclusively, to monitoring the operation of a conveyor belt installation wherein the belt is a steel cord reinforced belt. It may, however, be employed with belts reinforced by other relatively magnetically permeable materials, the expression “relatively magnetically permeable” being used herein to refer to a reinforcement permeability which is greater than that of the belt material which is reinforced by said reinforcement.
One problem commonly experienced in the use of conveyor belts employed to transport heavy or sharp items, such as quarried or mined material, is that the belt is exposed to the risk of puncture. If the item causing puncture becomes wedged relative to the conveyor support structure instead of moving with the belt, there is a particular risk that the belt will then be longitudinally slit as it passes the wedged object, and much expensive damage will result.
Another problem encountered is that over a period of time the reinforcement members are at risk of deterioration. Although typically the steel cords or other reinforcing members are embedded in the elastomeric material of a belt, if, for example, that embedding material becomes degraded or locally damaged there is a risk of water or other damaging material or fluid coming into contact with and degrading the reinforcement. In consequence the belt will cease to function properly and in due course may break.
To avoid or minimise the risk of breakage or other potentially dangerous situations arising it is known to over-design the reinforcement so that even following a predicted degree of reinforcement degradation, the reinforcement remains safe for use and break resistant over a period of time which at least equals the likely period for which the belt cover material is expected to remain in a serviceable condition. That over-design is, however, undesirable because it increases the weight and cost as well as reducing flexibility of the belt, and also fails accurately to safeguard against a possible premature part or total failure of the reinforcement.